In a recent development, NTT Corporation unveiled the “first” gigahertz ultrasonic circuit that utilizes topological insulator principles, indicating a new era in ultrasonic communication technology.

To use this circuit adjust 4k7Ω Resistor at resonance frequency of the piezo transducer for maximum amplitude of the repeller ultrasonic sound. At 11 KHz to 22kHz this can reach a value of 10Vpp and ...